1. Field of the Invention
The present invention relates to NCO-free resins and coatings possessing the outstanding performance characteristics of polyurethanes.
2. Discussion of the Background
For the past several decades, urethane coatings, blocked urethanes, etc. have been very successfully used as polymers for coating and engineering polymers. They have been formulated to achieve outstanding results for the industry.
Most commonly, urethanes are prepared by a reaction in which free isocyanates (NCO) are reacted with various other groups in a two-package system. Recent environmental toxological studies however indicate that it is very desirable to eliminate free NCO groups from uncured polymers coatings. This would prevent exposure of this toxic material to humans during manufacture, application and in the final product, and the product would be very stable because no NCO groups would be available to react with moisture, etc. To date no satisfactory solution to this problem is available.
There is thus a strongly felt need for NCO-free resins and coatings possessing the outstanding performance of urethane materials. Notably there is a strongly felt need for NCO-free resins ad coatings possessing the following advantages: high gloss, high impact resistance, good hardness and flexibility, good solvent and chemical resistance, good UV resistance in weathering, and good room temperature cure.